The present invention relates to a mounting frame for a filter disposed at the front of the ceiling in a clean room.
Conventionally various clean rooms with a sufficiently purified space have been used widely in producing precision instruments, electronic parts such as LSIs, medicines or others. Although various types of clean rooms are known to the public, a laminar downflow type wherein purified air is fed vertically from an air port disposed at the front of the ceiling into the room is generally employed. In this case, a super clean room is realized wherein purified air is fed through a filter disposed on the overall surface of the ceiling. Although the filter generally used in a super clean room has a good filtering capacity because of glass fiber bonded by means of a binder, the binder possesses not only a peculiar odor, but glass fiber corpuscles may flow into the room and scatter therein because of the deterioration of the binder associated with aging. The filter now in use has the above-mentioned disadvantages.
Since in a conventional clean room, the filter is fixed in a mounting frame hung from the ceiling, and since the circumference of the filter is sealed with a sealing compound, purified air cannot pass through the vicinity of the mounting frame, standing air is easily formed in the lower part of the mounting frame, and a vortex flow of floating dust is formed downstream of the mounting frame that may lower the purity of air.
It is an object of the present invention to provide a filter mounting frame which itself works as a filter and forms no standing air downstream thereof.
In order to attain said object, a filter mounting frame for a clean room is constructed of a hard material molding having a strength capable of supporting the filter and also having an air filtering resistance comparable to that of the filter according to the present invention.
For the mounting frame, materials having an air filtering resistance comparable to that of a high performance filter are used. Materials such as alumina or stainless sintered material, porous glass and FRP meet the requirement. By applying an air permeable sealing material to the stepped part of the mounting frame, in contact with the high performance filter, the overall front of the ceiling becomes a filter.